well ok, then consult the spec in your owners manual, don't have an OM then enter your vin on the HD site and view the OM there...which is where you will find the right answer to your question instead of opinions of strangers in the internet trust the manufacturer instructions

 

It sure can, Been using Rotella 15W-40 since 2003 for applications that require a 40w oil. Wet clutch (engine oil) bikes too. For the HD I have been using Mystik 15W-50 semi synthetic.
Just bought a 5 gallon bucket of Mystik this summer.

 

A 12 year old thread. Oil threads never grow old. They are so full of T-rex bones? Or is it fern leaves?

 

Obviously this forum is here to help fellow riders and help answer many questions we might have. Or should I consult the manual about that too?

 

Do you use it in a Harley?

 

I would if I had no other choice. And in the Suzukis it's lubricating everything & getting crunched between the gears too. But the Suzukis call for 40 wt. I know people who use Rotella in their Polaris motors which call for 50 wt & haven't heard anything bad about it.